Chapter 4
Cutaneous Membrane
• Cutaneous membrane = skin
– Dry membrane
– Outermost protective boundary
• Superficial epidermis is composed of
keratinized stratified squamous epithelium
• Underlying dermis is mostly dense
connective tissue
Cutaneous
membrane
(skin)
(a) Cutaneous membrane (the skin)
covers the body surface.
Figure 4.1a
Connective Tissue
Membrane
• Synovial
membrane
– Connective tissue
only
– Lines fibrous
capsules
surrounding joints
– Secretes a
lubricating fluid
Ligament
Joint cavity
(contains
synovial fluid)
Articular (hyaline)
cartilage
Fibrous
capsule
Synovial
membrane
Articular
capsule
Integumentary System
• Skin (cutaneous membrane)
• Skin derivatives – sweat glands, oil glands,
hair & nails
• Protects deeper tissue from: bumps,
chemicals, bacteria, UV rays, heat/cold,
dessication
• Skin functions - aids in heat loss &
retention, excretion of urea, synthesizes
vitamin D
5
Skin Structure
• Epidermis – outer
layer
– Keratinized, stratified
squamous epithelium
• Dermis - dense
connective tissue –
where tattoos are
placed!
• Subcutaneous Layer
(Hypodermis)
6
Skin Structure
Where do we find tattoos?
Hair shaft
Dermal papillae
Epidermis
Papillary
layer
Dermis
Pore
Appendages of skin
• Eccrine sweat gland
• Arrector pili muscle
• Sebaceous (oil) gland
• Hair follicle
• Hair root
Reticular
layer
Hypodermis
(superficial fascia)
Nervous structures
• Sensory nerve fiber
• Lamellar corpuscle
• Hair follicle receptor
(root hair plexus)
Cutaneous vascular plexus
Adipose tissue
7
Two Layers of the Dermis:
• Papillary layer
– Upper dermal region, uneven with
fingerlike projections (papillae)
– Papillae have capillary loops for
nutrients & gas exchange
– Contain free nerve endings (pain) &
Meissner’s corpuscles (touch)
– Give you your finger & foot prints
• Reticular
Layer
•Deepest skin layer
•Contains blood vessels, sweat & oil glands
•Phagocytes travel the area consuming bacteria
8
Melanin
• Pigment (melanin) produced by
melanocytes (cells that produce melanin)
• Color is yellow to brown to black
• Sunlight triggers melanin production
• Excessive sun:
– damages the skin
– makes it leathery
– depresses the immune system
9
Appendages of the Skin
• Sebaceous glands – exocrine glands (have ducts)
– Produce oil – found everywhere except palms/soles
– Most with ducts that empty into hair follicles, some
onto skin.
– Glands are activated at puberty
– Produce sebum (oil & fragmented cells)
• Keeps skin soft & moist
• Keeps hair from getting brittle
• Has chemicals that kill bacteria
– Whitehead/blackhead = plugged sebaceous duct
– Acne – active infection of sebaceous glands
10
Appendages of the Skin
• Sweat glands (sudoriferous glands)
– Widely distributed in skin
– TWO TYPES:
• Eccrine Glands – more numerous, all over body
– Produce sweat (water, salts, vit. C, urea, lactic
acid)
– Acidic pH 4-6, to prevent bacterial growth
– HELPS REGULATE BODY TEMP.
• Apocrine Glands – in axillary & genital regions, larger
than eccrine
– Sweat plus fatty acids & proteins, bacteria
consume these causing an odor
– DO NOT help with temperature regulation, function
not precisely understood
11
Sweat
pore
Sebaceous
gland
Eccrine
gland
Dermal connective
tissue
Sebaceous
gland duct
Hair in
hair follicle
Secretory cells
(a) Photomicrograph of a sectioned
sebaceous gland (14×)
12
Control of Body Temperature
• Blood vessels – blood vessels in reticular
layer of dermis will dilate (open up) during
increased body temperatures
– Heated blood near skin surface allows heat to
leave the body via evaporation of sweat, face
appears flushed or red
– Blood vessels will constrict (close) during low
body temperatures, conserving heat
• Eccrine Glands – produce sweat in
response to elevated body temperature
13
Skin Cancer-The most common type
of cancer
• Cancer – abnormal cell mass
• Two types of tumors:
– Benign – cells are not able to metastisize
(move to new location)
– Malignant – cancerous cells that can
metastisize (move to new location)
Risks:
1. Skin type
2. Sun exposure
3. Family history
4. Age
5. Immunological status
http://science.nationalgeo
graphic.com/science/heal
th-and-humanbody/human-body/skinarticle/
14
Skin Cancer Types
• Basal cell carcinoma – least malignant and
most common
– bump with pearly edge, rarely metastisizes, surgery
15
Skin Cancer Continued
• Squamous cell carcinoma – rapid growth,
metastisizes to lymph nodes
– Scaly, red areas forming an ulcer, common on scalp,
ears, hands & lower lip
– Surgery + radiation
16
Skin Cancer Continued
• Malignant melanoma – cancer of melanocytes,
spreads rapidly, often deadly
– 5% of skin cancer is this type, often from pigmented
mole
Normal mole
Malignant Melanoma
17
ABCD Rule –for recognizing melanoma
• A = Asymmetry – sides of mole do not match
• B = Border irregularity – no smooth borders
• C = Color – different colors, reds, tans, black,
brown
• D = Diameter – larger than 6 mm
• You want moles to be symmetrical, smooth
borders, one color and small!!
18
Skin Homeostatic Imbalances
• INFECTIONS:
– Athletes foot – fungal infection, red & itchy
– Boils and carbuncles – inflammation of hair follicle &
sebaceous glands caused by bacteria
– Cold sores – caused by herpes simplex (viral) infection,
can be activated by UV rays, anxiety, fever
• Infections and allergies
– Contact dermatitis – Red & blistering skin reaction to an
allergen – poison ivy, detergent, etc.
– Psoriasis – Overproduction of skin cells, red skin
w/silvery scales, may be autoimmune, genetic link
19
Skin Homeostatic Imbalances
• BURNS:
– Tissue damage and cell death
caused by heat, electricity, UV
radiation, or chemicals
– Associated dangers
• Body loses supply of fluids
(proteins & electrolytes)
• Infection
• RULE
OF NINES: 11 areas of the body with 9%
value each, + 1% perineum
•The higher the % the greater the risk of
complications and death.
20
Severity of Burns
• FIRST-DEGREE BURNS – partial thickness burn,
epidermis damaged, red & swollen, 2-3 days to heal,
“sunburn”
• SECOND-DEGREE BURNS – partial thickness burn,
epidermis and papillary layer burned, red with blisters
– Regrowth usually occurs with little to no scarring
• THIRD-DEGREE BURNS – full thickness burn, area is
blackened or gray/white, no pain (nerve endings burned
off)
– Grafting must be done, scarring
• Burns are considered critical if: over 25% of body has 2nd
degree burn, over 10% has 3rd degree burns or 3rd degree
burns on hands/face/feet
21
http://www.youtube.com/watch?v=eXO_Apj
KPaI&safe=active (the skin gun)